Battery less vs. battery based grid tie

[BB.]

Hmm... If the Sunny Island "GT system" responds within a few seconds... Then it really needs the Sunny Island Inverter+Battery system to carry through the starting loads... Which only makes sense as the "true" GT / Utility Interactive systems apparently have a "fairly long" time constant (per a Solar Guppy post in another thread, probably to prevent oscillations between the inverter and utility power).

An Off-Grid inverter would need to respond within 1/2 cycle (1/120 Hz = 8.3 mSec) to be a "useful power source" for an off grid system.

-Bll

[stephendv]

Not sure if we're talking about the same response here, I meant the response to varying the GT output based on the loads when already operating in off-grid mode. And in this case the GT has to be a sunny boy.
E.g.: Grid is down, batteries fully charged, GT and AC loads and SI are all on the same AC bus. Frequency is now controlled by the SI. If the loads are less than the GT then the time it takes for the SI to increase the frequency and the GT to reduce it's output correspondingly is only a few seconds.

EDIT: Ah, I think I see what you mean now, yes the SI will have to carry the loads through until the GT can respond.

[Dave Sparks]

If you have to have two inverters it really make little sense for my "hypothetical" customer. I am thinking that with the modern slow start refrigerators someone would devise a way to avoid spoiling food and batteries.

I like the idea of no driving at night Bill, not sure about the tunnel part yet...

[RCinFLA]

One thing that came to mind....

Solar Maxima is coming 2011-2012. Some predictions are it will be worse since 1958.

Demand for power distribution transformers may go up.

[tallgirl]

Originally Posted by RCinFLA

One thing that came to mind....

Solar Maxima is coming 2011-2012. Some predictions are it will be worse since 1958.

Demand for power distribution transformers may go up.

Huh? Which predictions, and which way "worse"?

Besides, the likelihood we reach Solar Max in 2011 or 2012 is close to nil. We still setting records for "boring". This cycle would have to get past the "Yawn" level of excitement first.

[dwh]

Actually, NASA and NOAA are predicting the peak of Cycle 24 in May 2013. It's not supposed to be a particularly high peak, but they think there is a good chance of a few pretty big flares.

http://www.swpc.noaa.gov/SolarCycle/SC24/index.html